Any expectations related to Arsenal are actually too much because we all know that Arsenal started the season quite well but they don't have the mentality of being champions, several failures are the basic reason for doubts about them.
But in the future, no one knows what it will be like it clear that for UCL, I myself won't have much hope for Arsenal because there is team that is much stronger and can be favored as team with quite big chance of success.
If Arsenal are indeed able to win the title next season, perhaps only in the Premier League and not the UCL, my estimate is that Arsenal will probably only finish the UCL competition like last season, where they were eliminated before entering the semifinals.
Moreover, even though have lot of expensive players, if are not able to use them well it will be waste, players are very influential on the development of football team, but solid and consistent performance would be much better.
Arsenal "might" succeed in the Premier League but not going no where near the Champions League title. Manchester City are not having their primary aim targeted at the Premier League, already won four in a row what more do they need, I feel they are willing to sacrifice the PL title for the Champions League, having lost to Madrid, guess we don't plan seeing that happen again.
Football is not about how much worth a player, players can be bountifully purchased but under perform, take a look at some Chelsea players. Arsenal has the squad but they feel a lot relaxed once they begin topping the table.
If Arsenal again fails to meet expectations in the Premier League and Champions League next season, in my opinion Arteta deserves to be fired, and Arsenal must have the courage to spend more money to appoint a more experienced coach. Arteta main priority is to end the Premier League title drought which has lasted for two decades, the Champions League trophy is still too difficult for them. The existence of Manchester City makes it difficult for Arsenal dreams to be realized at the domestic level, especially in the Champions League which has more elite teams. However, what Arteta has done in the last two seasons deserves appreciation, he has succeeded in managing Arsenal to get better every season. We realize that Arsenal has all the attributes needed to achieve success, but the front line of Arteta squad still needs to be improved.